JWST confirms changing water clouds on brown dwarf WISE 0855
Using the James Webb Space Telescope, a team led by Brittany Miles of the University of Arizona tracked WISE 0855 for 11 hours, recording its light every 15 minutes. The observations confirmed that high-altitude water clouds change thickness as the brown dwarf rotates, while carbon monoxide and phosphine also fluctuate as gases rise from deeper layers, according to the study in The Astrophysical Journal.
Bottom line — The team plans further JWST observations to map WISE 0855’s rotation and the three-dimensional movement of its atmosphere.
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WISE 0855 is about 7.5 light-years away and roughly twice Jupiter’s mass, according to the study team.
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At about 265 kelvins (−8°C), WISE 0855 is the coldest known brown dwarf, Phys.org reports.
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JWST’s medium-resolution spectrograph tracked changes in individual molecular features, which older telescopes could not resolve for an object this cold, the researchers say.
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The cloud and chemical signals vary together in the observations, but reflect distinct processes: rotation changes which cloud-covered regions are visible, while convection brings deep gases upward, according to the study.